Prove `16 cos pi/15cos(2pi)/15cos(4pi)/15cos(8pi)/15=-1`

"cos(pi/15)cos((2pi)/15)cos((4pi)/15)cos((8pi)/15)=k

cos(pi/5)cos((2pi)/5)cos((4pi)/5)cos((8pi)/5)=

Find the value of 16cos(pi/15).cos((2pi)/15).cos((4pi)/15).cos((8pi)/15)

Prove: cos(pi/15)cos((2pi)/15)cos((3pi)/15)cos((4pi)/15)cos((5pi)/15)cos((6pi)/15)cos((7pi)/15) = 1/2^7

Prove that: cos(pi/5)cos((2pi)/5)cos((4pi)/5)cos((8pi)/5)=(-1)/16

Prove that, 16 "cos" (2pi)/15 "cos" (4pi)/15 "cos" (8pi)/15 "cos" (16pi)/15 =1

If the value of "cos"pi/15"cos"(2pi)/15"cos"(3pi)/15"cos"(4pi)/15"cos"(5pi)/15"cos"(6pi)/15"cos"(7pi)/15 is (1)/(2^(k)) , then which of the following is true ?

Prove cos2pi/15cos4pi/15cos8pi/15cos16pi/15=1/16

Prove that :16cos2(pi)/(15)cos4(pi)/(15)cos8(pi)/(15)cos16(pi)/(15)=1

Prove that cos(2pi)/(15)cos(4pi)/(15)cos(8pi)/(15)cos(14pi)/(15)=1/(16)